The two historical and largest churches of the country are the Roman Catholic Church and the Protestant Evangelical Church in Germany (EKD).

Roman Catholicism was the sole established religion in the Holy Roman Empire until the advent of the Protestant Reformation which changed this drastically. In the early 16th century there was much discontent occasioned by abuses such as selling indulgences in the Catholic Church, and a general desire for reform. In 1517 the Reformation began with the publication of Martin Luther’s 95 Thesis which detailed 95 assertions Luther believed to show corruption and misguidance within the Catholic Church. It demonstrated Luther's disagreement both with the way in which the higher clergy, especially the pope, used and abused power, and with the very idea of the pope.